Feeler apparatus for controlling wrench rotation



Oct. 20, 1953 s. P. JOHNSON 2,655,827

FEELER APPARATUS FOR CONTROLLING WRENCH ROTATION Filed July '11. 1952 2 Sheets-Sheet i INVENTOR SIDNEY I? JOHNSON I 36 1 3 7 ATTORNEYS S. P. JOHNSON Filed July 11, 1952 2 Sheets-Sheet 2 FIG. 6.

INVENTOR. $IDNY P. JGHNSON Patented Oct. 20, 1953 UNITED STATES ATENT OFFICE FEELER APPARATUS FOR CONTROLLING WRENCH ROTATION Sidney P. Johnson, Washington, D. 0.

Application July 11, 1952, Serial No. 298,484

This invention relates to tools and more particularly to a wrench for accurately rotating a nut or the like a small predetermined amount.

The described invention may be manufactured and used by and for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.

It has been found that, when pipe flanges are bolted together, an undesirable torsional stress sometimes remains in the tightened bolts and this stress should be relieved if the coupling is to have maximum holding strength. In fact, certain pipe-fitting and coupling instructions often require this relief by specifying that the nuts on the bolt-studs be backed off one-half a degree. However, in practice, such requirements for the most part were ignored or intentionally overlooked because of the inability of the mechanic to estimate the necessary degree of loosening and the dangers inherent in any excessive loosening. Some special tools which deal generally with such problems have been proposed, but these operate on an entirely different principle in that they are concerned solely with assuring an initial tightness of the nut rather than with relieving strain by loosening the nut a predetermined amount.

Accordingly, one of the broader objects of this invention is to provide a wrench by means of which a nut or the like may be rotated in either direction any accurately gauged amount; while a more specific and related object is to provide a wrench capable of backing-off nuts a small fractional part of a turn sufficient to relieve undesirable torsional stresses in the bolt on which it is mounted.

Further objects are to provide a wrench that can easily be adjusted to fit over the nut to be moved; that can be used for different-sized nuts; and which is simple to operate and economical to construct.

Other objects of this invention will be readily appreciated by reference to the detailed description.

In accordance with the invention, the wrench embodies a nut-engaging portion and extensible thrust and stop members adapted to be brought into engagement with any available fixed surface lying in proximity to the nut. In operation, the wrench is engaged with the nut, and the stop member adjustably set at a predetermined distance from the fixed surface, which, in elfect, is both a referencing and supporting surface. The thrust member then is brought up to and forced thrust reacting on the wrench in the manner to be expected to cause it to rotate to the limit of its stop member. The stop member does not have to be a type having a fixed feeler settable with its inner end a predetermined distance from the reference surface and then swung into physical contact with that surface. Instead, it may be found desirable to reverse this operation and obtain an indication, by means of a spacer plate or dial, of the distance by which a stop member having an initially engaged feeler moves away from that surface. In fact, for some purposes it may be found preferable to utilize a stop member having a plunger-type feeler adapted to maintain constant contact with the reference surface during the whole time that the stop member as a unit is swung toward or away from this surface, and the wrench-limiting factor in such an instance may be provided by variations in the pressure exerted on the feeler by that surface. Preferably, the gripping jaws of the wrench are formed on suitable removable and replaceable adapters or bushings sized to engage nuts of various diameters, and the adapters are so formed as to permit the nuts to be engageable regardless of their angle of rotation with respect to the wrench.

The preferred form of the invention is illustrated in the accompanying drawings, of which Fig. 1 is a'plan view showing the tool operatively engaging a pipe flange nut; Fig. 2 a side elevation of the Fig. 1 assembly; Fig 3 a sectional View taken along line 3-3 of Fig. 2, Fig. 4 a perspec tive view of the nut-receiving bushing, Fig. 5 a gauge that may be used for indicating the amount of nut movement; and Fig. 6 is a plan view of a modified wrench.

Referring to the drawings, the wrench, generally designated by numeral I 0, is formed of an elongate arm or body l2 provided centrally with head portion l4 adapted to grip and loosen nuts, such as nut 22, used to couple a pipe flange [6 to an adjacent flange, or the like. The nuts are engaged or gripped by a bushing l8, that is provided with a nut-receiving socket 20, the bushing 18 being removably received in a recess 24 formed in the body portion of the wrench.

The action of the wrench relies in part upon the previously referred to fixed reference surface in that, before the wrench isoperated, it must be set in a certain position with respect to this surface, rotation of the wrench from that position determining and conforming to the desired degree of nut rotation. In the assembly shown in Fig. 1, the fixed surface is pipe flange l6, although, in other adaptations the fixed surface can be any surface that lies proximate to the nut, or, if desired, the wrench itself could be provided with a fixed surface.

The configuration or shape of the wrench will depend somewhat upon the principal purpose for which it is intended, the wrench illustrated being somewhat arcuate in shape and having oppositely extending arm portions 32' and 34 projecting laterally from the central portion of its body. As may be seen, these arms are set at a slight angle so as to permit them to bebrought into a spaced relationship with respect to the pipeflange against which the wrench is used. Arm 32 mounts a thrust member 36 which, asshown, simply is a threaded bolt havinganoperators handle 31, secured at its outer end, the inner end of this bolt being adapted to flushly engage pipe flange I5. Opposite arm 34, similarly, is provided with a threaded opening to receive a set screw 38 that is adapted to be adjustably fed through the arm by a knurled head 40.

The manner in which this wrench is 'used should be somewhat apparent from the foregoing description. Its primary purpose is, as has been stated, to relieve undesirable torsional stresses set up in bolts by the tightening of the nuts on them. These stresses must be relieved and the present wrench is adapted to relieve them by gripping the nuts and backing them off the exact degree required. To engage the nuts 2. suitable adapter or bushing 18, which is sized to fit the nut being loosened, is selected, this adapter being fitted over the nut and then by teeth '25 engaged with corresponding teeth 25 of the recessed body portionof the wrench. As may be appreciated, the nut rarely will 'lie in the par ticular rotated position shown in Fig. 1, but, such an eventuality easily accommodated since the wrench can be fitted in avariety of positions over the adapter after it has been mounted on the not. For this purpose it'is desirable to use rather closely-spaced teeth so as to increase the number of positions'in which the adapter and the wrench can :be int ermes'hed.

With the nut :eng-ag-ed, arms 3 2 and 34 will lie in their spaced relationship to pipe flange t6 and thrust member 3 6 may be fed inwardly toward the flange to bring its inner end in :contact with it. The degree that the wrench is to be turned, however, "is a ftmction of .set screw, or stop 38 and'this stop is adjusted until its inner endlies a certain spaced distance from its radially adjacent flange surface. Such a spacing is designated by small are'X (Fig.1) which is determined'both by the dimensions .of the wrench and the desired degree of backing-off of the nut. For example, with a wrench having :a designed dimension of three inches from the center of nut '22 to the contact point of set screw 3'8, the spacing required'to back-off a nut zone-half degree of rotation 71.30.0262 inch and, for other wrenches and other 'desired rotations suitable charts readily can be prepared.

With set screw or stop 38 fixed in its predetermined position, nut 22 may be loosened the precise amount desired simply by rotating the handle of thrust member 36, this rotation forcing the thrust member inwardly against flange 16 of the pipe and causing the wrench to rotate about the axi of nut 22 until the rotation is stopped by engagement of the inner end of stop 38 with the pipe flange.

In actual practice it has been found desirabl in order to obtain a precise setting of stop 38. to first force thrust member 36 into such a firm contact with pipe flange l6 that any looseness between bushing l8 and the nut is taken up. With this looseness taken up, set screw 38 can be adjusted accurately by inserting a suitable spacer plate (not shown) between stop member 38 and the outer surface of the flange, this plate being removed after it has been contacted by the stop. Of course, the spacer must have a thickness equal to the desired X spacing.

Fig. 5 illustrates a modified form of a stop member 38 in which the necessity of using such a spacer plate is avoided by the use of a suitable dial gauge '42 that can be calibrated in inches or in. degrees to give a direct reading of the spacing of its inner end. Such mechanism is obtainable commercially and should need no detailed description.

If felt desirable, an operable tool would be provided even if both the thrust and the stop memhere were disposed on the same side of the body portion although, in such an event, the degree of rotation would'be the amount by which the stop member moved away from its fixed reference surface. Such a modification is illustrated in Fig. 6 which shows a wrench 44 having .a head portion 35 formed at one end of a body 48, a thrust member 5t and :a stop member 52 being mounted on the same side of the :body. Stop member 52 may include a set screw, such as screw 38 of Fig. 1, in which event the degree of rotation (in counter-clockwise direction) would meassure the amount the set screw is moved away from the fixed reference surface; or, if desired, the stop member may include .a conventional engagement with the fixed reference surface during wrench movement whereby to indicate the movement of the stop member ratchet mechanism 5.8 may be provided on the handle so when turning space is not available.

The advantages of the present wrench are raher obvious in, that. primarily, a simple, inexpensive and easily-used tool is provided for producing any minute degree of rotation desired. The-above description has been with reference to the-use ofthetool for backing-off tightened nuts. but it will be appreciated that the tool could easily :be adapted for turning most any rotatable object; Further, it will be appreciated that the function of the thrust and the stop members could :be accomplished :by many other which are intended to he-within the compass of the invention.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

Iclaim.

1. A wrench for turning a rotatable head mounted in proximity to .a fixed support, said wrench comprising an arm formed to grip said head, a stop having a feeler member, and a thrust member, said members being adjustably projected outwardly from said arm toward said fixed support and said thrust member being adapted to be forced against said fixed surface when said head is gripped, whereby said stop can be set a predetermined distance from said support and said thrust member forced against the surface, said force causing the wrench to swing :gaguut the axis of said head to the limit of said 2. A wrench for turning a rotatable head mounted in proximity to a fixed support, said wrench comprising an arm having an intermediate portion adapted to grip the head, a stop having a feeler member and a manually operable thrust member, each member being adjustably carried at opposite end of said arm and projecting outwardly therefrom toward said fixed support, whereby said wrench can be engaged with said head with said feeler member set a predetermined distance from said fixed support, said thrust member then being movable into contact with and thrust against said fixed support to swing reactively said arm about the axis of said engaged head until the feeler member engages the support.

3. A wrench for turning a rotatable head mounted in proximity to a fixed support, said wrench comprising an arm having an intermediate portion adapted to grip the head, a stop having a ieeler member, and a manually operable threaded member, each member being adjustably carried at opposite ends of said arm and projecting outwardly therefrom toward said fixed support, whereby said wrench can be engaged with said head and said feeler member set at a predetermined distance from said fixed support, said threaded member then being movable into contact with and thrust against said fixed support to swing reactively said arm about the axis of said engaged head until the feeler member engages the support.

4. A wrench for turning a rotatable head mounted in proximity to a fixed support, said wrench comprising a body having an intermediate portion adapted to grip the head, a stop having a feeler member and a manually operable thrust member each member being adjustably carried at opposite ends of the body and projecting toward said fixed support, said stop having an indicator dial, whereby said thrust member can be moved into contact with the support and said feeler member set by means of the dial a predetermined distance from the support, said thrust member being movable toward said support to rotate the body about the axis of said engaged head until the feeler member engages the support.

5. A wrench for turning a rotatable head mounted in proximity to a fixed support, said wrench comprising a body having a detachable bushing formed to grip said head, a stop having a feeler member and a manually operable thrust member, each member being adjustably carried at opposite ends of the body and projecting toward said fixed support, whereby said thrust member can be moved into contact with the support and said feeler member set a predetermined distance from the support, said thrust member movable toward said support to rotate the body about the axis of said engaged head until the feeler member engages the support.

SIDNEY P. JOHNSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 937,317 Rea et a1 Nov. 9, 1909 1,462,377 Painter et a1. July 17, 1923 2,244,185 Bakewell June 3, 1941 2,420,132 Gryniuck Ma 6, 1947 2,492,470 Farkas Dec. 27, 1949 2,562,831 Stone July 31, 1951 2,602,361 Meyer et a1. July 8, 1952 FOREIGN PATENTS Number Country Date 4,162 Great Britain 1904 

